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From "Alex Behm (Code Review)" <>
Subject [Impala-ASF-CR] IMPALA-4076: Fix runtime filter sort compare method
Date Fri, 07 Oct 2016 01:02:24 GMT
Alex Behm has posted comments on this change.

Change subject: IMPALA-4076: Fix runtime filter sort compare method

Patch Set 2:

File fe/src/main/java/org/apache/impala/planner/

Line 341:       }
> We are checking the cardinality of the child left child (the potential dest
The equation is trying to get the selectivity from cardinalities. Only doing a division is
not sufficient because it doesn't correctly capture the 0 cardinality case. So the math is
wrong, and we need an extra check to compensate. I maintain that the selectivity should be
0 if one side of an inner join has a 0 cardinality.

Think about it this way: Returning -1 will discard the most selective runtime filters.
File testdata/workloads/functional-planner/queries/PlannerTest/runtime-filter-propagation.test:

Line 1123: # so the number of runtime filters has to be greater than 32 and they have to be
in a
> I don't think it would silently fail, because the plan would change. But ju
You are right, let's remove setting the query option in PlannerTest, sorry.

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Gerrit-MessageType: comment
Gerrit-Change-Id: Iad433f2ece423ea29e79e81b68fa53cb0af18378
Gerrit-PatchSet: 2
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Taras Bobrovytsky <>
Gerrit-Reviewer: Alex Behm <>
Gerrit-Reviewer: Taras Bobrovytsky <>
Gerrit-HasComments: Yes

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